March 8, 2015Yellowstone Convention Center - Big Sky, MT

Large Volume, Optical and Opto-Mechanical Metrology Techniques for

ISIM on JWST

Theo HadjimichaelOptics Branch

NASA Goddard Space Flight CenterGreenbelt, Maryland

OutlineI. INTRODUCTION

II. PURPOSE AND ALIGNMENT PLANIII. REQUIREMENTS

IV. METHODS AND TOOLSV. TESTS, MEASUREMENT AND SETUP

VI. ANALYSISVII.RESULTS

VIII.DATABASESIX. CONCLUSION

Integrated Science Instrument Module (ISIM) Element

ISIM consists of:– Five sensor systems

• MIRI, NIRCam, NIRSpec, NIRISS, FGS– Nine instrument support systems:

• Optical metering structure system• Electrical Harness System• Harness Radiator System• ISIM Electronics Compartment (IEC)• Cryogenic Thermal Control System• Command and Data Handling System

(ICDH)• ISIM Remote Services Unit (IRSU)• Flight Software System• Operations Scripts System

ISIM is one of three elements that together make up JWST • Approximately 1.4 metric tons, ~20% of JWST by mass

ISIM CV2 Presentation to PIT: R. Ohl/GSFCUse of data disclosed on this page is subject to restriction(s) on the title page of this document22 Jan 2015 3

4

(flight-like)

ISIM Element

ElectricalHarness

RadiatorBaffle

ThermalStraps

KinematicMounts

ISIMElectronics Compartment (IEC)

Fine Guidance Sensor (FGS) andNear Infrared Imager and Slitless Spectrograph (NIRISS)

Mid-InfraredInstrument(MIRI)

Near Infrared Camera (NIRCam)

Near-Infrared Spectrograph (NIRSpec)

ISIM CV2 Presentation to PIT: R. Ohl/GSFCUse of data disclosed on this page is subject to restriction(s) on the title page of this document22 Jan 2015

ISIM images from SSDIF, prior to CV2

MIRI

IECHR

NIRCam

FGS/NIRISS

NIRSpec

5ISIM CV2 Presentation to PIT: R. Ohl/GSFC

Use of data disclosed on this page is subject to restriction(s) on the title page of this document22 Jan 2015

ITP

Fine Guidance Sensor (FGS)Near Infrared Imager and Slitless Spectrograph (NIRISS)Near Infrared Camera (NIRCam)Near-Infrared Spectrograph (NIRSpec)Mid-Infrared Instrument (MIRI)

ISIM Structure

Harness Radiator (HR)ISIM Electronics Compartment (IEC)ISIM Test Platform (ITP); ground support equipme

ASMIF and ISIM• Instrument were built on a GSE (Ambient Science Insturment

Mechanical Interface Fixture, ASMIF) that mimics the ISIM-SI interface

• Identical Science Instrument Interface Plates (SIIP) were fabricated for the ASMIFs and ISIM structure

Science InstrumentsNIRCam

FGS

MIRI

NIRSpec

Ground Support Equipment (GSE)Master and ISIM alignment target fixture (MATF/IATF) Targets tracked and used to align optical simulator to ISIM

V1

V2

V3

LIFTHOIST

MATFCFMP

LT/PGTARGET

ITP MOUNT

ADM TARGETHOLDER

OAAF

IATF-5IATF-OC1

IATF-6

IATF-1IATF-OC2

IATF-2

IATF-3IATF-OC3

IATF-4

IATFADM-1

IATFADM-3

IATFADM-4

MCA

IATFADM-2

V2

V3

V1

ISIM I&T Flow (1/2)CV2

Summer 2014

Science Instrument Rework

FGS:• Detectors• Electronic

s boards

NIRISS• Detector• Grisms• Dual

WheelMotors

MIRI:• Flight

HSA• Electronic

s boards

NIRCam:• A2 detector,

ASIC, or cable

• Electronics boards

NIRSpec:• Detectors• MicroShutt

er Array

Environmental Testing• Vibration (ISIM Prime, Harness Radiator, IEC separately)• Acoustics (together)• EMI/EMC (together)

AmbientFunctional

CV3Summer/Fall 2015

DeliveryEnd 2015

CV1-RRSummer/Fall 2013

Integration of Full-Up ISIM

22 Jan 2015

Data analysis and final reports

Winter/Spring 2016

Softwarechanges

ISIM I&T Flow (2/2)

M = ambient metrology

22 Jan 2015

Purpose of Work• Verify the ambient 6 degree of freedom (DOF) alignment of the SIs

to the ISIM structure• This is done using various metrology targets located on the ISIM

structure and each SI– Interchangable spherically Mounted Retroreflector (SMR) and Tooling Ball (TB)

nests– Optical alignment cubes– Locations calibrated relative to precision mechanical interfaces

• In addition, each instrument contains a pupil alignment reference (PAR) that is measured near the nominal predicted ambient OTE exit pupil location

• Build a comprehensive database of tracking targets through all environmental testing

Requirements• Uncertainties are determined via a bottoms up

estimation and are compared to expectations allocated from the top-level ISIM requirements

• Overall test requirement is that the measured SI nests and cube locations are at their predicted locations within the 2-sigma uncertainties of:– The SI optical bench (OB) and Ground support equipment (GSE)

measured locations when integrated to ISIM– The SI OB measured locations while integrated to the ASMIF

structure– Finite element modeling (FEM) of the above two orientations

with respect to gravity– Misalignment associated with small differences in ASMIF and

Structure precision mount interfaces

Methods and Tools• A variety of measurement tools are used depending on the

application and requirements• Tools used include: Leica laser trackers (LT), Nikon laser radar (LR),

Leica Wild T3000 theodolites and a Koll Morgen alignment telescope (AT)

• LR is typically used for measurements of the SI optical benches (OB) and ISIM structure TB targets

• LT was used for PAR measurements primarily for its ability to track an SMR for alignment purposes

• Theodolites were used for all optical cube face measurements• Photogrammetry Cameras used during both ambient and cryogenic

testing

Ambient metrology tools: Laser trackers and theodolitesLaser tracker1 is used to measure targets and surfaces• Operated with Spatial Analyzer2 software, which includes Unified Spatial Metrology Network (USMN; bundling) routine --- greatly improved uncertainty• Its target is a spherically mounted retro-reflector (SMR) that attaches to magnetic nest that are interchangeable with the TB targets that are used by the LR• Uncertainty ~0.005--0.025 mm (1-sigma)•LT may be used with T-Cam / T-Scan / T-Probe accessories to measure envelopes, surfaces, tooling holes•May also be used to track hardware during “blind” precision integration activities (Transtrac)

Theodolites are used to measure angles via auto-collimation and targets via triangulation• Operated manually, data is analyzed with GSFC-developed software• Autocollimation: Target is a specular flat mirror (cube)• triangulation: Target is scribe cross hair or specular tooling ball• Uncertainty ~2 arc-sec (1-sigma) for a single measurements, >5 arc-sec (1-sigma) for a collection of measurements

1. Leica Geosystems AG, Heerbrugg, Switzerland, metrology.leica-geosystems.com2. New River Kinematics, Inc., Williamsburg, Virginia, www.kinematics.com

SMR

Laser tracker

Theodolite

pc1

Slide 14

pc1 add LR photo descriptionpcoulter, 7/8/2014

Ambient metrology tool: “Laser radar”

Laser radar1 (LIDAR) is used to measure targets and surfaces

• Operated with Spatial Analyzer software• Its target is diffuse surface (mechanical surface;

matt finish), reflective tooling ball, specular mirror, or high-quality tooling hole

• Uncertainty ~0.010 mm in range (1-sigma), ~0.015 mm per meter in azimuth and elevation (1-sigma)

• Laser Radar scans much faster than Laser Tracker with T-Probe

• USMN-compatible• At ambient, used for:

• Used for prescription and alignment measurement for large optics (radius, aperture, etc.)

• Envelope scans• Tooling ball targets on large assemblies

Laser radar (LIDAR)

1. Nikon Metrology Inc, http://www.nikonmetrology.com/en_US

Invar+BR127 Kapton blanket Tube Mylar blanketJWST materials test article

TB/nest

Photogrammetry Overview• 3 dimensional metrology system• Uses triangulation to locate

custom targets in 3 coordinates• Requires multiple camera

locations• Solves for the camera locations

and coordinates of the targets simultaneously through the bundling procedure contained in the V-STARS software, proprietary software owned by Geodetic Systems Inc.

• Software contains calibration algorithms to calibrate internal camera errors

• Geometrically diverse scalebarsprovide scale

Measurement Setups• Measurements conducted in the NASA GSFC Space

Systems Development and Integration Facility (SSDIF) and Space Environment Simulator (SES) chamber

• Tests– GSE only ambient/cryogenic characterization– Full multi-station LR measurements of SI OB and

ISIM structure targets– Full suite of theodolite measurements of all SI OB

cubes and ISIM structure cubes– Five sets of measurements taken at each station– Resulting final values used for PAR measurements

MATF and IATF (xATF) ambient testing

Vertical and Horizontal calibration of allTargets

MATF and IATF (xATF) Cryogenic Testing

Warm to cold changes of xATF SGR, Mirror, Pinohole and Invar Scalebars tracked in LN chamber fitted with a LHe shroud.

Photogrammetry in SES chamber

Computer with labview interface

ISIM structure with PG targets and scalebars

Boom assembly and camera supports

INCA3 Camera

Canister

Structure characterization, ambient

• Ambient measurement of the SI populated structure on ITP in SSDIF

– Structure contains metrology targets and some limited harnessing (e.g., temperature sensors)

– Invar, GSE corner fitting metrology plates (CFMP) with integral alignment cubes

– LT targets (GSE nests) on CFMPs and tubes

– Most CFMPs remain on Structure throughout I&T

– Each SI contains metrology nest targets

– Each SI contains two optical cubes

ISSD

CAD image of ISIM Structure+ITP+ISSD+IMIS

IMIS

V1

V3Structure

6 reference B targets (CFMPs; 6th on rear corner, facing away)

KM

CAD image of invar GSE CFMP

Tooling hole for interchangeable LT nest and PG target with tapped holes for capture

Orthogonal mirror faces, polished invar

ISIM

SIs

Top View of Test Setup

SIs not shown

=Theodolite

PAR Measurement Setup

PAR Breadboard Top View

Test Setup

Gravity Release

ISIM in turnover fixture

Slowly rotated using Ransome Table

ISIM and SI tooling balls and cubesMeasured V1 up then V1 down and compared FEM modeling.

Analysis• TB/SMR Data analyzed using Spatial Analyzer1

• PG Data analyzed with VStars• Multiple stations were combined using USMN2, 3

– Bundling technique similar to photogrammetry applications– Can be used for multiple types of instruments

• ISIM nest target values best-fit transformed to an as-built unpopulated ISIM structure database

• Theodolite data analyzed using Microsoft Excel• Theodolite data brought into VCS via direct and through measurements

using the transfer cube assembly (TCA)• Students-t (2-sigma)4 uncertainty calculated from five sets• FEM differences from gravity are accounted for in the results• Differences in the coordinate system due to the SIIP from ASMIF to ISIM

are accounted for in the results1. New River Kinematics, Inc., Williamsburg, Va.2. S. Sandwith & R. Predmore, “Real-time 5-micron Uncertainty with Laser Tracking Interferometer Systems using Weighted

Trilateration,” New River Kinematics, Inc. Williamsburg, Va.3. Spatial Analyzer User Manual, page 322, v. 2013.12.09.4. J. Hayden et al., “Measurements and Analysis used for the Determination of the James Webb Space Telescope Integrated

Science Instrument Module Vehicle Coordinate System,” Coordinate Metrology Society Conference, July 2010.

GSE Targets: Pinholes

Ambient Pinhole measurements with CathetometerCryogenic with LR vision scan(output pictured above)

GSE Targets: SGR

GSE Targets: SGR

Diagram and data from LR scan of an SGR

GSE Targets: SGR

• Fit plane to range points• Fit lines to facet

interfaces• Create point at line/plane

interface• Average 3 points

• Correct for transmission through glass

PAR Analysis• Analysis starts with the final USMN average results from the TB/SMR survey of the structure• Measurements are made of all visible ISIM structure targets during the PAR measurements

and are best-fit transformed to the final USMN results of the ISIM survey• The measured pupil target location is used as the basis for image analysis• ImageJ software is used for the image analysis.• Five images taken with illumination altered between images for each PAR

Measured Nominal Pupil LocationPAR target center

AT crosshairs aligned to V2/V3 axis via clocking reference

PAR Analysis• PAR images from all instruments• PAR targets are not perfectly aligned to the SI pupil. The offsets are known• All SIs are not designed to image well at ambient

Results

• ISIM structure data presented is from the pre-cryovac 2 testing (May 2014)• Pre-CV1 prime—FGS, MIRI• Pre-CV1—FGS, MIRI• Post-CV1—FGS, MIRI (PAR only)• Pre-CV2 prime—All SIs• Pre-CV2—All SIs• Post-CV2 (Fall 2014)—All SIs

• FEM difference due to the different SI orientation and loading conditions are accounted for in the results.

Example of development of pass/fail values for nest location measurements

Example of development of pass/fail values for cube face orientation measurements

PAR Image Location Pass/Fail Criteria

• Based on relative test to test changes• Defined in the entrance pupil space• ISIM level requirement for pupil shear is 3.1%• To put this into perspective the pass fail values for V2/V3 converted

to pupil shear percent is 0.16%. This is a factor of 20 better than the absolute alignment requirement for pupil shear

OTE exit pupil diameter

PG System Measurement Uncertainty

0.015 mm

2 sigma error in determining warm to cold scalebar length change based on scalebar calibration error budget

0.029 mmPG As-Built 2-sigma measurement error

0.005 mm

Estimate of maximum target location change in hole due to cool down

0.132 mm2 sigma error budget allocation to PG system measurement uncertainty

0.025 mm

2 sigma uncertainty between measured and calculated warm to cold scalebar length changes

0.011 mmPG target 95% measurement uncertainty

0.012 mm

VSTARS target 2-sigma network error propagated across 5 datasets

0.033 mm 2 sigma as-built PG warm-to-cold measurement uncertainty for Cryoset Test

0.009 mm0.008 mmWarm Cold

ISIM Coordinate System

ISIM and SI TB/SMR Results

From Pre-CV1

ISIM/SI Cube Results

Database Build

Summary• We have successfully verified the SI-level target calibration is in good

agreement with measured SI OB locations on ISIM element to better than the required pass/fail values

• This process will be repeated during ISIM level I&T to trend any potential alignment changes due to thermal cycling (CV2, CV3), vibration and acoustic exposure

• This process will also be repeated after SI work during I&T.

AcknowledgementsThe author gratefully acknowledges the collective contributions of the optical, mechanical, and systems engineering, management, and science teams working on the James Webb Space Telescope, Integrated Science Instrument Module element, and specifically:

J. Gum, T. Hadjimichael, J. Hylan, T. Madison, L. Miner, R.G. Ohl, J. YoungNASA Goddard Space Flight Center, Greenbelt, Maryland

M. MaszkiewiczCanadian Space Agency

A. BeatonComdev International

S. Hummel, M. Melf, A. RoedelEADS Astrium Gmbh

M. Te PlateEuropean Space Agency

P. SchweigerLockheed Martin Corporation

K.F. Mclean, J. McMann, K. Redman, G.W. WenzelQinetiq North America

J.E. HaydenSigma Space Corp., Lanham, Maryland

P.W. WilliamsSGT International

D. Lee, M. WellsUK Astronomy Technology Centre

This work is supported by the James Webb Space Telescope project at NASA Goddard Space Flight Center.

Questions?Thank you for your attention.

Theo HadjimichaelOptics Branch

NASA Goddard Space Flight CenterGreenbelt, Maryland

Theodore.j.hadjimichael@nasa.govtel. 301 286 5681

Back up Slides

• MIRI ASMIF: Delivered to RAL, May 2007• NIRSpec ASMIF: Delivered to Astrium, Sep 2007• FGS ASMIF: Delivered to COM DEV, Dec 2007• NIRCam ASMIF: Delivered to Lockheed Martin, Jan 2009

MIRI VM with ASMIF at RAL

ASMIF status

NIRSpec ASMIF post-shipment calibration check and OBK installation at Astrium

FGS ETU with ASMIF at COM DEV, Ottawa

NC bench installed on ASMIF at LMCO

Master gauge for nominal OTE-ISIM interface (“reference A”)Fiduciary points on KM sockets map to MICDUsed for ambient integration, metrology and alignment (SSDIF)Used for cryogenic testing in both Structure cryo-set and Integrated ISIM testingSupported by IMIS and ISSD in SSDIF for ambient workSupported by Upper GESHA in SES chamber for cryogenic testing~30K ITP is attached to the ~100K Upper GESHA via thermal isolator stand-offsSupports MATF for OSIM-to-reference A alignmentExtensive optomechanical requirements related to alignment and stability

Hoist points

OTE-ISIMkinematicmount socket

Metrology targetsV1

V3

CAD image of ITP

ISIM KM strut and OTE interface

ISIM Test Platform (ITP)

CAD image of OTE-ISIMkinematic mount socket and invar mounting block

Coordinate system and ISIM hardware

ISIM VBREFERENCETO ISIM

ITP VAREFERENCETO OTEINTERFACE

ISIM

ITP

ISIM KM

ISIM/OTE INTERFACEBASED ON SPHERICALSEAT LOCATIONS

DEFINED USING 8PG/LT TARGETS

DEFINED USING 6 KMSPHERICAL SEATLOCATIONS

ITP

V3

KMP1 KMP2KMP3

KMP4

KMP5

KMP6

ITP MOUNTLEG

OPTICALCUBE

ISIM KMMOUNTAND BLOCK

MATF

ISIM

V-coordinate system is mapped to surrogate backplane (ISIM Test Platform fixture; ITP) via least-squares fitMapping is redefined for different load and temperature configurations (significant warm-to-cold change and gravity sag)

Simulation of ITP metrology (top view, looking in +V1 direction; SSDIF)

ITP calibration, ambient

CAD image of ITP+ISSD+IMISshowing metrology references

V3

V1

Ambient calibration of ITPDefinition of V-coordinate system using interface references and MICDCalibration of ITP metrology references using LT, theodolites, PGCube normals are aligned to approximately represent axes of V-coordinate system

Changes to ambient calibrationVarious load cases (empty, bare Structure, Integrated ISIM, OSIM’s BIA)Repeatability with handling and mounting

MATF installationCalibrate 6 DoF alignment with respect to V-coordinatesRepeatability of attachment

ISIM Error Budget Report (JWST-RPT-008175) documents allocations for ITP metrology uncertainty (knowledge) and impact to flight hardware alignment

Simulation of ITP metrology (side view; SSDIF)

Extraction from MICD showing 1 KM interface

Alignment approach for SI-to-Structure(Ambient Science Instrument Mechanical Interface Fixture; ASMIF)

• Alignment of SI optical train relative to SI-ISIM interface is verified by SI developer using optomechanical tooling (i.e., ASMIF)

• Levy requirements on Structure to avoid iterative compensated cryogenic alignment (i.e., no “windage” within Structure --- no pre-alignment at ambient to achieve correct placement at cryogenic operating temperature)

• Place SI-Structure interface plats on the ground at ambient at their nominal on-orbit alignment positions and orientations --- differences between warm vs. cold structure and loaded vs. 0g structure are small and captured in error budget

• Measure bare Structure cryogenic performance to verify that it meets alignment requirements and increase confidence in Integrated ISIM performance (Structure’s “cryo-set” test)

FGS ETU with ASMIF at COM DEV, Ottawa

Ambient integration of SIs with Structure

Simulation of metrology for NIRSpec instrument integration

SIs are integrated to StructureIntegrated ambient baseline metrology performed after Structure is populated with SIs: SI optical bench and ISIM Structure targets are measured using laser trackers and theodolites at ambient temperature under 1-gMeasurements are compared with expectations based on

SI+ASMIF metrology resultsAs-built ITP, Structure, and SI validated mechanical models (e.g., gravity sag, ITP distortion)

Measurements, including uncertainty, must agree with as-built mechanical models and “blueprints”This step ensures that SIs are where they should be in Structure at ambient under 1-g

CAD view of Integrated ISIM showing NIRSpec side of assembly